Natalia Shakhova

Natalia Shakhova
University of Alaska Fairbanks

About

98
Publications
19,864
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
3,184
Citations

Publications

Publications (98)
Article
Significant reserves of methane (CH4) are held in the Arctic shelf, but the release of CH4 to the overlying ocean and, subsequently, to the atmosphere has been believed to be restricted by impermeable subsea permafrost, which has sealed the upper sediment layers for thousands of years. Our studies demonstrate progressive degradation of subsea perma...
Article
Full-text available
Seeps found offshore in the East Siberian Arctic Shelf may mark zones of degrading subsea permafrost and related destabilization of gas hydrates. Sonar surveys provide an effective tool for mapping seabed methane fluxes and monitoring subsea Arctic permafrost seepage. The paper presents an overview of existing approaches to sonar estimation of meth...
Article
Full-text available
The Ob-Irtysh River system is the seventh-longest one in the world. Unlike the other Great Siberian rivers, it is only slightly impacted by the continuous permafrost in its low flow. Instead, it drains the Great Vasyugan mire, which is the world largest swamp, and receives huge load of the Irtysh waters which drain the populated lowlands of the Eas...
Article
Full-text available
Destabilization of intrapermafrost gas hydrates is one of the possible mechanisms responsible for methane emission in the Arctic shelf. Intrapermafrost gas hydrates may be coeval to permafrost: they originated during regression and subsequent cooling and freezing of sediments, which created favorable conditions for hydrate stability. Local pressure...
Article
Full-text available
This paper summarizes current understanding of the processes that determine the dynamics of the subsea permafrost–hydrate system existing in the largest, shallowest shelf in the Arctic Ocean; the East Siberian Arctic Shelf (ESAS). We review key environmental factors and mechanisms that determine formation, current dynamics, and thermal state of sub...
Article
Full-text available
Destabilization of intrapermafrost gas hydrate is one possible reason for methane emission on the Arctic shelf. The formation of these intrapermafrost gas hydrates could occur almost simultaneously with the permafrost sediments due to the occurrence of a hydrate stability zone after sea regression and the subsequent deep cooling and freezing of sed...
Article
Full-text available
Black carbon (BC) contributes to Arctic climate warming, yet source attributions are inaccurate due to lacking observational constraints and uncertainties in emission inventories. Year-round, isotope-constrained observations reveal strong seasonal variations in BC sources with a consistent and synchronous pattern at all Arctic sites. These sources...
Article
Full-text available
Sonar surveys provide an effective mechanism for mapping seabed methane flux emissions, with Arctic submerged permafrost seepage having great potential to significantly affect climate. We created in situ engineered bubble plumes from 40 m depth with fluxes spanning 0.019 to 1.1 L s⁻¹ to derive the in situ calibration curve (Q(σ)). These nonlinear c...
Article
Full-text available
More than 12 000 measurements of the dissolved methane (CH4) concentrations in the surface waters of Northern Eurasian marginal seas (Barents, Kara, Laptev, Chukchi, and Bering Seas, Sea of Okhotsk, and Sea of Japan) during two marine expeditions (September-October 2011 and 2012) show that all seas are CH4 source to the atmosphere, but the Laptev a...
Article
Full-text available
Sea-surface temperature and salinity (SST/S) in the Arctic Ocean (AO) are largely governed by sea-ice and continental runoff rather than evaporation and precipitation as in lower latitude oceans, and global satellite analyses and models which incorporate remotely-observed SST/S may be inaccurate in the AO due to lack of direct measurements for cali...
Conference Paper
Full-text available
Among Arctic carbon reservoirs, subsea permafrost, hydrates, and associated methane (CH4) deposits are the most worrisome owing to high heat transfer from rapidly warming shallow Arctic seas. The East Siberian Arctic Shelf is a big portion of the Arctic shelf and hosts over 80% of current subsea permafrost and along with it, unique Arctic shallow C...
Article
Full-text available
Sustained release of methane (CH4) to the atmosphere from thawing Arctic permafrost may be a positive and significant feedback to climate warming. Atmospheric venting of CH4 from the East Siberian Arctic Shelf (ESAS) was recently reported to be on par with flux from the Arctic tundra; however, the future scale of these releases remains unclear. Her...
Article
Full-text available
Sustained release of methane (CH4) to the atmosphere from thawing Arctic permafrost may be a positive and significant feedback to climate warming. Atmospheric venting of CH4 from the East Siberian Arctic Shelf (ESAS) was recently reported to be on par with flux from the Arctic tundra; however, the future scale of these releases remains unclear. Her...
Article
Full-text available
On the basis of perennial studies, the features of formations of suspended particulate matter fields were revealed depending on the evolution of synoptic processes and the river runoff. The variability in the content and distribution structure of suspended particulate matter during the ice-free period depends on variable mobilization and the contri...
Article
The rapidly changing East Siberian Arctic Shelf (ESAS) receives large amounts of terrestrial organic carbon (OC) from coastal erosion and Russian-Arctic rivers. Climate warming increases thawing of coastal Ice Complex Deposits (ICD) and can change both the amount of released OC, as well as its propensity to be converted to greenhouse gases (fueling...
Article
The problem of the current state of subaerial morphosculptures on the periglacial East Siberian Shelf is still debatable due to the lack of in situ data. Therefore, any new information contributes to the knowledge of the evolution of the Arctic environment. In view of this, a complex of interdisciplinary ocean-ological studies was carried out in th...
Article
Full-text available
Vast quantities of carbon are stored in shallow Arctic reservoirs, such as submarine and terrestrial permafrost. Submarine permafrost on the East Siberian Arctic Shelf started warming in the early Holocene, several thousand years ago. However, the present state of the permafrost in this region is uncertain. Here, we present data on the temperature...
Article
Full-text available
This study aims to improve understanding of carbon cycling in the Buor-Khaya Bay (BKB) and adjacent part of the Laptev Sea by studying the inter-annual, seasonal, and meso-scale variability of carbon and related hydrological and biogeochemical parameters in the water, as well as factors controlling carbon dioxide (CO2) emission. Here we present dat...
Preprint
Full-text available
Methane is a strong greenhouse gas emitted by human activity, but also by natural processes. Large uncertainties exist on the future contribution of natural methane sources (e.g. wetlands and geological sources) to the radiative forcing of the Earth. The Arctic regions are of special concern, because they undergo above average warming causing the t...
Article
Full-text available
In 2011, a marine interdisciplinary expedition on the R/V Akademik M.A. Lavrentyev was carried out in the eastern Arctic seas. The expedition was conducted within the framework of the project of targeted basic investigations under the aegis of the Russian Founda� tion for Basic Research. These investigations regis� tered intense methane blowouts re...
Article
Full-text available
This study aims to improve understanding of carbon cycling in the Buor-Khaya Bay (BKB) by studying the inter-annual, seasonal, and meso-scale variability of carbon stocks and related hydrological and biogeochemical parameters in the water, as well as factors controlling carbon dioxide (CO2) emission. Here we present data sets obtained on summer cru...
Article
Full-text available
The paper presents the actual values of the thermal conductivity of sediments of the upper horizons of the Laptev’s Sea shelf permafrost. The data have been obtained during researches in the Buor-Khaya Bay to the East from the Muostah island under the Russian-American project of studying of the methane potential in seas of the eastern Arctic. The t...
Article
Full-text available
On the basis of the analysis of published data and in the course of the authors’ long-term geochemical and acoustic surveys performed in 1995–2011 on the East Siberian shelf (ESS) and aimed to research the role of the Arctic shelf in the processes of massive methane outbursts into the Earth’s atmosphere, some crucially new results were obtained. A...
Article
Full-text available
The future trajectory of greenhouse gas concentrations depends on interactions between climate and the biogeosphere. Thawing of Arctic permafrost could release significant amounts of carbon into the atmosphere in this century. Ancient Ice Complex deposits outcropping along the ~7,000-kilometre-long coastline of the East Siberian Arctic Shelf (ESAS)...
Article
Most ancient organic carbon and methane hydrates are stored in continental shelf deposits, particularly in the arctic shelves, where they are sequirested beneath and within the sub-sea permafrost. The largest, shallowest, and thus most vulnerable fraction of methane deposits occurs on the East Siberian Arctic Shelf (ESAS). The ESAS sub-sea permafro...
Article
The East Siberian Arctic Shelf (ESAS) is home to the world's largest hydrocarbon stocks, which consist of natural gas, coal bed methane (CH4), and shallow Arctic hydrates. Until recently, the ESAS was not considered a CH4 source due to the supposed impermeability of sub-sea permafrost, which was thought to completely isolate the CH4 beneath from mo...
Poster
Full-text available
Destabilization of permafrost is one of the few mechanisms that can redistribute significant amounts of carbon among the Earth's reservoirs within this century, contributing to the build-up of greenhouse gases and potentially enhancing global warming. Ancient Ice Complex (IC) deposits in the Siberian Arctic and shallow subsea permafrost on the East...
Article
Full-text available
This review paper summarizes current understanding of the transport of organic carbon to, and the fate of organic carbon within, the East Siberian Arctic Shelf (ESAS), and of processes determining carbon dioxide (CO2) and methane (CH4) fluxes from the ESAS to the atmosphere achieved from analyzing the data sets obtained on 20 expeditions performed...
Article
Full-text available
The high-latitude, shallow ESAS has been alternately subaerial and inundated with seawater during glacial and interglacial periods respectively. Subaerial conditions foster the formation of permafrost and associated hydrate deposits whereas inundation with relatively warm seawater destabilizes the permafrost and hydrates. Our measurements of CH4 in...
Article
Full-text available
The present day interest in understanding whether and how methane, preserved in seabed reservoirs, can escape to the atmosphere suggests a need to review sub-sea permafrost observations and to re-examine available sub-sea permafrost models. Currently, the models of sub-sea permafrost evolution significantly vary in employed physical assumptions reg...
Article
The chosen borehole (71 41N, 130 21E) characterizes the morphological structure of the tectonic fractal zone that is filled in with "acoustically gassy sediments". We suggest this site exhibits a significant potential to release CH4 into the atmosphere because this area belongs to the Gakkel Ridge so-called "Middle Arctic belt", a linear seismicall...
Article
Full-text available
The Lena River integrates biogeochemical signals from its vast drainage basin, and the integrated signal reaches far out over the Arctic Ocean. Transformation of riverine organic carbon (OC) into mineral carbon, and mineral carbon into the organic form in the Lena River watershed, can be considered to be quasi-steady-state processes. An increase in...
Article
Full-text available
Shelf seas are among the most active biogeochemical marine environments and the East Siberian Sea is a prime example. This sea is supplied by seawater from both the Atlantic and Pacific Oceans and has a substantial input of river runoff. All of these waters contribute chemical constituents, dissolved and particulate, but of different signatures. Se...
Article
Full-text available
Shelf seas are among the most active biogeochemical marine environments and the East Siberian Sea is a prime example. This sea is supplied by seawater from both the Atlantic and Pacific Oceans and has a substantial input of river runoff. All of these waters contribute chemical constituents, dissolved and particulate, but of different signatures. Se...
Article
Full-text available
The Lena River integrates biogeochemical signals from its vast drainage basin and its signal reaches far out over the Arctic Ocean. Transformation of riverine organic carbon into mineral carbon, and mineral carbon into the organic form in the Lena River watershed, can be considered a quasi-equilibrated processes. Increasing the Lena discharge cause...
Poster
Full-text available
The widest and shallowest East Siberian Arctic Shelf (ESAS) acts as an important region for producing and processing of organic matter before the material is transported into the Arctic Ocean. Up to 100% of the total organic carbon (TOC) in the ESAS sediments is terrestrial by origin (TOCterr). TOCterr flux in the ESAS integrates riverine and coast...
Article
A 2009 multibeam sonar survey of the shallow water-column (mean depth 10 m), near-coastal region of the East Siberian Arctic Shelf (ESAS) adjacent to the Lena River Delta detected tens of thousands of widespread bubble plume seeps. The ESAS contains an estimated 1400 GT (109 tons = 1 GT) of carbon sequestered within and beneath a sub-sea permafrost...
Article
The East Siberian Arctic Shelf (ESAS), which includes the Laptev Sea, the East-Siberian Sea and the Russian part of the Chukchi Sea, is an unique area of the World Ocean in terms of its potential to alternate atmospheric methane fluxes if Arctic shallow permafrost-related hydrates destabilize. There are three different types of hydrates in the ESAS...
Article
Full-text available
The East Siberian Arctic Shelf (ESAS), which includes the Laptev Sea, the East Siberian Sea, and the Russian part of the Chukchi Sea, has not been considered to be a methane (CH4) source to hydrosphere or atmosphere because subsea permafrost, which underlies most of the ESAS, was believed, first, not to be conducive to methanogenesis and, second, t...
Article
Full-text available
Sustained release of methane to the atmosphere from thawing Arctic permafrost likely is a strong positive feedback to climate warming. A climate impact of Arctic methane releases is implied by past climate shifts and may play a role in the renewed growth of contemporary atmospheric methane. Observed Arctic warming in early 21st century is stronger...
Article
Full-text available
We present some results of our biogeochemical and hydrological studies conducted in the East Siberian Arctic seas (ESAS) in 1994-2008, and along the Lena River stream during July-August, 2003 and after flood season in late August-early September, 1995 and 1998. We focus on the carbon cycle, including horizontal dissolved and particulate organic and...
Article
Until recently, the East Siberian Arctic Shelf (ESAS) was not considered a CH4 source due to the impermeability of subsea permafrost, which completely isolated it from modern biogeochemical cycles. The ESAS is home to the world's largest hydrocarbon stocks, mostly as shallow Arctic hydrates, and thus represents an enormous potential CH4 atmospheric...
Article
The ESAS sub-sea permafrost stability is a key element in controlling methane flux from the seabed deposits to the water column and further to the atmosphere. Currently, there is very few observational data on the ESAS sub-sea permafrost state and thermal regime. We present a model of permafrost dynamics to explain limited observations and to gain...
Article
The Arctic Ocean is surrounded by permafrost, which is being degraded at an increasing rate under conditions of warming which are most pronounced in Siberia and Alaska . A major constraint on our ability to understand linkages between the Arctic Ocean and the global climate system is the scarcity of observational data in the Siberian Arctic margina...
Article
The East Siberian Arctic Shelf (ESAS), the widest and shallowest ocean shelf in the world, is an important region for producing and processing organic matter before the material is transported into the Arctic Ocean. Up to 100% of the total organic carbon (TOC) in the ESAS surface sediments is terrestrial by origin (TOCterr). TOCterr flux in the ESA...
Article
Full-text available
The present state of sub-sea permafrost modeling does not agree with certain observational data on the permafrost state within the East Siberian Arctic Shelf. This suggests a need to consider other mechanisms of permafrost destabilization after the recent ocean transgression. We propose development of open taliks wherever thaw lakes and river paleo...
Article
Full-text available
Remobilization to the atmosphere of only a small fraction of the methane held in East Siberian Arctic Shelf (ESAS) sediments could trigger abrupt climate warming, yet it is believed that sub-sea permafrost acts as a lid to keep this shallow methane reservoir in place. Here, we show that more than 5000 at-sea observations of dissolved methane demons...
Article
Full-text available
The East Siberian Arctic Shelf (ESAS), which includes the Laptev Sea, the East Siberian Sea, and the Russian part of the Chukchi Sea, has not been considered to be a methane (CH4) source to hydrosphere or atmosphere because subsea permafrost, which underlies most of the ESAS, was believed, first, not to be conducive to methanogenesis and, second, t...
Article
Full-text available
Remobilization to the atmosphere of only a small fraction of the methane held in East Siberian Arctic Shelf (ESAS) sediments could trigger abrupt climate warming, yet it is believed that sub-sea permafrost acts as a lid to keep this shallow methane reservoir in place. Here, we show that more than 5000 at-sea observations of dissolved methane demons...
Article
Full-text available
Results of data analysis, based on measurement of atmospheric concentrations of methane in the shallow part of the East Siberian shelf (ESS) are presented in this work. It was shown that methane emission in the atmosphere is determined not only by natural factors, but is also sensitive to anthropogenic influences, like the engine mode of a ship. It...
Article
Bacteriohopanepolyols (BHPs) are a diverse group of membrane lipids produced by a wide variety of bacteria and can be used as molecular biomarkers for bacterial processes and populations in both modern and ancient environments. A group of BHPs, including adenosylhopane and structurally related compounds, have been identified as being specific to so...